Cindy is making a punch for a party. The recipe calls for 3 bottles of cranberry juice in order to make enough punch to serve 40 guests. How many bottles of cranberry juice will Cindy need in order to make enough punch to serve 100 guests?
Answer ___________ bottles

so.....
3/40 = x/100 ????
i already know to solve this proportion thing it's just that I want to make sure if I'm setting this up right.